Bell 407 N1371 accident near Chauvin, Louisiana

Probable cause

The pilot's failure to maintain proper altitude resulting in a collision with water for reasons that could not be determined based on the available information.

NTSB analysis

The commercial pilot was repositioning the helicopter from an offshore oil platform to the operator's home base in visual meteorological conditions. When the helicopter did not return as expected, the operator initiated a search; the helicopter wreckage was found in a shallow marsh area just off shore. No radio distress calls were received from the pilot, and the skid-mounted emergency float system was not deployed. Onboard flight-following equipment recorded a straight flight path tracking directly to the intended destination with a gradual descent just prior to impact.

Accident flight data extracted from the helicopter's engine control unit did not show any faults with the engine. Detailed examinations of the helicopter's airframe, drive system, and flight controls did not reveal any preimpact anomalies. Examination and full teardown of the engine did not reveal any anomalies and indicated that the engine was operating at the time of impact.

Airframe deformations were consistent with a slightly nose-low and left-skid-down attitude at the time of impact; therefore, it is unlikely that the pilot experienced a loss of control. Given the absence of mechanical anomalies, the fact that the pilot did not make a distress call or activate the emergency float system, and the helicopter's relatively straight recorded flight path, it is likely that the helicopter was operating normally at the time of impact. Further, toxicology testing and autopsy findings did not indicate any evidence of pilot impairment. It could not be determined why the pilot failed to recognize the helicopter's descent and maintain a proper altitude above the water.

Text from the NTSB. Open the NTSB docket for CEN17FA112 for the full record.